Qual é o propósito de usar CommandType.Tabledirect

CommandType contém nomes que especificam como uma string de comando é interpretada.

CommandType.Text para um comando de texto SQL. (Padrão.)
CommandType.StoredProcedure para o nome de um procedimento armazenado.
CommandType.TableDirect para o nome de uma tabela .

Todas as linhas e colunas da tabela nomeada serão retornadas quando você chamar um dos métodos Execute.

NOTA:TableDirect é suportado apenas pelo .NET Framework Data Provider para OLE DB . O acesso a várias tabelas não é suportado quando CommandType é definido como TableDirect .

Exemplo de exemplo de como está sendo usado:

OleDbConnection myOleDbConnection =new OleDbConnection("provider=sqloledb;server=(local)\\SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI");
OleDbCommand myOleDbCommand = myOleDbConnection.CreateCommand();

myOleDbCommand.CommandType = CommandType.TableDirect;

myOleDbCommand.CommandText = "Employee";

myOleDbConnection.Open();

OleDbDataReader myOleDbDataReader = myOleDbCommand.ExecuteReader();

for (int count = 1; count <= 2; count++)
{
  myOleDbDataReader.Read();
  Console.WriteLine("myOleDbDataReader[\" ID\"] = " +
    myOleDbDataReader["ID"]);
  Console.WriteLine("myOleDbDataReader[\" FirstName\"] = " +
    myOleDbDataReader["FirstName"]);
  Console.WriteLine("myOleDbDataReader[\" LastName\"] = " +
    myOleDbDataReader["LastName"]);
}
myOleDbDataReader.Close();
myOleDbConnection.Close();

Inserir/Atualizar

        try
        {
            using (SqlCeCommand command = conn.CreateCommand())
            {
                command.CommandText = "Holdings";
                command.CommandType = CommandType.TableDirect;
                using (SqlCeResultSet rs = command.ExecuteResultSet(ResultSetOptions.Updatable | ResultSetOptions.Scrollable))
                {
                    SqlCeUpdatableRecord record = rs.CreateRecord();
                    foreach (var r in _commitBatch)
                    {
                        int index=0;
                        record.SetValue(index++, r.TryGetValueOrDefault("IdentifierFromImportSource",string.Empty));
                        record.SetValue(index++, r.TryGetValueOrDefault("SecurityID", string.Empty));
                        record.SetValue(index++, r.TryGetValueOrDefault("SecurityName", string.Empty));
                        record.SetValue(index++, r.TryGetValueOrDefault("SecurityType", string.Empty));
                        record.SetValue(index++, r.TryGetValueOrDefault("AllocationAmount", string.Empty));
                        record.SetValue(index++, r.TryGetValueOrDefault("Position", string.Empty));
                        record.SetValue(index++, r.TryGetValueOrDefault("AnnualFeePercent", string.Empty));
                        record.SetValue(index++, r.TryGetValueOrDefault("MarginAmount", string.Empty));
                        record.SetValue(index++, r.TryGetValueOrDefault("Price", string.Empty));
                        record.SetValue(index++, r.TryGetValueOrDefault("MorningstarSecId", string.Empty));
                        record.SetValue(index++, r.TryGetValueOrDefault("MorningstarSecType", string.Empty));
                        record.SetValue(index++, r.TryGetValueOrDefault("UserID", string.Empty));
                        record.SetValue(index++, r.TryGetValueOrDefault("MorningstarPrice", string.Empty));
                        record.SetValue(index++, string.Empty);
                        record.SetValue(index++, r.TryGetValueOrDefault("AnnualFeeFrequency", string.Empty));
                        record.SetValue(index++, r.TryGetValueOrDefault("TrackingMethod", "1"));
                        rs.Insert(record);
                    }
                }

            }

        }
        catch (Exception e)
        {
            NotifyError(this, new ImportErrorEventArgs(e.Message + e.StackTrace, ErrorLevel.Application));
        }